Pressure limiting valve

Abstract

What is disclosed is a a pressure limiting valve comprising a valve body, the axial movement of which is damped by means of a damping device. In accordance with the invention, the damping device includes a damping chamber formed on the return side, that is subjected to the system pressure acting on a pressure port.

Description

INTRODUCTION[0001]The invention relates to a pressure limiting valve in accordance with the preamble of claim 1.BACKGROUND[0002]Pressure limiting valves serve to limit a system pressure. They may have the form of directly controlled seat valves. Other designs are spool valves or disk valves. These, too, may fundamentally be vibrationally damped by the kind of damping presently applied, if they are controlled directly. Furthermore the piloted design is also possible. When a pre-set maximum pressure is exceeded, a connection from a pressure port to a return port is opened via the pressure limiting valve. In the most simple case the pressure limiting valves are controlled directly and thus have a simple construction and may be manufactured at low cost. Such directly controlled pressure limiting valves have high opening dynamics, so that pressure peaks in the system may be reduced very rapidly. It is one drawback of these pressure limiting valves, however, that they are very prone to vi...

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Benefits of technology

[0008]In contrast, the invention is based on the object of furnishing a pressure limiting valve in which the damping effect is enhanced.

Problems solved by technology

It is one drawback of these pressure limiting valves, however, that they are very prone to vibration due to their opening dynamics in the event of pressure fluctuations.

The valve bodies, which vibrate owing to hydraulic excitation, may result in a considerable acoustic load, and in unfavorable cases in the destruction of an associated valve seat or of the spring acting in the closing direction.

This pressure medium volume balance is impaired by the throttle effect in the damping gap, with kinetic energy of the valve body and of the damping piston being converted into heat, and the axial translation of the valve body thus being decelerated and damped.

It is a drawback in this known solution that the axial structural space of the pressure limiting valve is increased by the damping chamber connected on the pressure port side and having the damping piston arranged in it.

Moreover a comparative technological complexity is necessary in the manufacture, for the pressure port has to be formed by oblique bores that are difficult to produce.

It is a drawback in this return-side low-pressure damping that 100% filling of the damping chamber with pressure medium must always be ensured.

This filling may only be carried out with comparative complexity during installation of the valve.

This risk is particularly high if the return line is capable of being emptied entirely, or if air dissolved in the pressure medium bubbles out in the transition from high pressure to low pressure.

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